Fuel burner



' R. C. VROOM ET AL Juy 27, 194s.

FUEL BURNER 2 Sheets-Sheet 1 Filed oct. 51, 1944 ORNEY R. C. VROOM ET AL Juy 27, 194s.'

FUEL BURNER Filied om. s1. 1944 2 Sheets-Sheet 2 Patented July `27, 1948 FUEL BURNER Robert C. Vroom, Montclair, and John Dunn, Tenaiiy, N. J., assignors to Peabody Engineering Corporation, New York, N. Y., a corporation of New York ,Application October 31, 1944, Serial No. 561,187

(Cl. 11o-104) 2 Claims.

l This invention relates to fuel burners yand has for an object to provide a burner for fuels in suspension of novel and improved construction which is stable over a wide range of capacities.`

` In accordance with the present invention a portionof the air forcombustion, or other gas, is supplied as a tertiary iiuid around the periphery of the burner throat in such a way as to shield the tile of the throat from the fuel stream and means are provided for causing the tertiary fluid to rotate in a controlled manner so as to maintain the desired fiame shape, When the tertiary fluid is air a richer mixture of fuel and secondary air is obtained than would be the case if all of the air for combustion were admitted through the burner tube, and more stable operationresults, particularly at the lower burner capacities.

The invention further provides a fuel admission chamber of larger diameter than the burner tube and having an end Wall extending entirely therearound which controls the fuel flow to the burner tube.

`Although thenovel features which are believed to be characteristic of this invention are pointed out more particularly `in the claims appended hereto,` the invention will be better understood by referring to the following description, taken in connection with the accompanying drawings in which a specific embodiment thereof has been set forth for purposes of illustration.

, 1 In the drawings,

Fig.' l is a longitudinal section through a burner embodying the present invention; and

Figs. 2 and 3 are transverse sections taken on the lines 2-2 and 3-3 respectively of Fig. 1.

Referring to the drawings, the construction shown comprises a Wind box front plate I which isseparated from a furnace wall II to provide a'wind box or plenum chamber I2 therebetween whichmayl be closed or open, depending upon whether the combustion air is to be supplied under 'a positive pressure or at atmospheric pressure. The furnace wall I I forms a part of a combustion chamber. To the wind box front plate I0 is attached as air register front plate I4 which carries an air register I5 of standard type having peripheral air doors I6 which are arranged to admit air from the wind box I2 to the interior of the air register, The doors I6 are shown as arranged conically about the periphery of the air register I5. It is to be understand, however, that they may be arranged cylindrically if desired. In the embodiment shown, the doors I6 are indicated as actuated in unison by a gear and pinion I'I which boss 28 having a pipe 2| through which a fuel atomizer barrel carrying liquid fuel extends. The atomizer barrel is provided at the furnace end with a tip which is suited to discharge fuel for combustion. A diffuser plate 23 of the usual form is shown as attached to the pipe 2l and its position is controlled by an operating rod connected to the hub of diffuser 23 as shown in Fig. 1. A

The air register I5 is provided with a throat piece 25 through which the rotating secondary air is discharged axially. The throat piece 25 opens into a pulverized fuel chamber 26 which is formed by a front transverse Wall Z'Iand a rear transverse baille Wall `28 joined by a peripheral Wall 29 Which is `arranged in the form of ya curve of decreasing radius as shown more clearly in Fig. 2. A fuel supply duct 30 opens tangentially into the fuel chamber 2B so as to supply pulverized or suspended fuel to said chamber and to cause the same to pass around the chamber and then to 'advance axially into a burner tube 35. The` wall 28 extends entirely around the burner tube 35 so that direct passage of fuel into the tube Without first flowing over the Wall 28 is prevented. The supply duct 38 is shown as attached by flanges 3| to a fuel supply pipe 32.

The burner tube 35 is provided at itsforward end with a -conical section 36 which is attached to the rear radial wall 28 of the fuel chamber 26 and extends at its furnace end into the burner throat 39 which is formed by a ring 0f tile 40 of standard construction. The free end of the burner tube 35 is spaced from the burner throat 39 to provide an annular uid passage 4I therebetween; A ring 34 is adjustably secured to the end of :the burner tube 35 for adjusting the admissionpjassage 4I. The ring 34 may be adjusted axially over the burner tube 35 for this purpose by a rod 63. f A cylindrical wall 45 extends between the wall 28 and a flange 45a attached to a furnace wall front plate 46 `which in turn is attached to the wall II of the furnace. This cylindrical wall 45 is spaced from the burner tube 35 to provide an"` annular chamber 4l therebetween which connects with annular passage 4I at the burner throat,

A pair of fluid supply ducts 48 (Fig. 3), which are arranged in diametrically opposite positions, are connected to supply air -or other fluid tangentially to the annular chamber 41, These ducts 48 may be open to the plenum chamber or windbox` I2 as shown (or may be supplied separately) and are provided with suitable dampers l) by means of which the amount of fluid supplied therethrough may be controlled. The dampers 5l), as shown in Fig. 2, are connected to levers 5i and links Waren-*operation in unison.= Thelinlgs 52 are pivotallykconnectedto a plate 53 which is pivoted at 54 to an ear 55 on the cylindrical wall d5. Plate 53 is attached to a control rod 56 which extends through the air register front plate I4 and is provided with a handle 51. fluid admission to chamber 4 1 either with out rotation may be provided.

A conical member t@ is attached to the air register throat piece and extends into the fuel chamber 26 to prevent fuel from entering the air register chamber. This member may be adjusted axially by an adjusting rod t4.

In addition, vanes 5i may be mounted between the burner vtube and the cylindrical wall d5 and adjusted by handles 62. These varies (il are adjustable through at least 180 so that the fluid supplied tothe passage il .from the chamber il may be caused to rotate in either direction or to ow without rotation as desired.

Operation In theyoperation of this device7 a stream of fuel suspended in carrier (primary) fluid is supplied through the `pipe 32 and the duct 3b to the fuel chamber 25 which, being of spiral form, causes the fuel to be evenly distributed as it rotates and passes over the baflie wall 28 into the burner tube .35. At the same time, secondary airffrom the plenum chamber l2 enters the air to be mixed with the fuel suspended in primary fluid `fromchamber 25 in the burner tube 35.

.This mixture of fuel with primary fluid and secondaryair then passes through the burner tube 35 and is discharged from the open end thereof at the ,burner throat 39 where combustion. takes place. Due to the tangential flow of fuel into the chamber 25 and to the rotation of the secondary air in the air register l5, the mixture of fuel and air rotates peripherally 'as it advances along the burner tube 35.

f The fuel emerging from the burner tube 35 is ignited initially by suitable means such as liquid fuel from the atomizer tip 22 and thereafter burns in a flame extending outwardly from the end of the burner tube. It is to be understood that after'ignition takes place, the fuel atomizer barrel may be retracted.`

If air is the tertiary fluid a` portion of the air inthe plenum chamber l2 passes through the dampers into the tertiary fluid chamber ll wherein it is likewise caused to rotate due to the tangential position of the air admission ducts 48 and the position of dampers 50. Tertiary fluid other than air may be supplied from a separate source. The tertiary fluid may rotate in either direction or may be supplied without rotation. This rotating tertiary fluid then advances along the outside of the burner tube 35 and discharges Other methods of closure purposes, and may be used without vanes 6I.

The rotation is also controlled by the Vanes 6l which, in conjunction with the tangential ducts 48 and dampers 50 may be adjusted to vary the ,degree of rotation concurrent with arl-counter to the fuel inthetube 35d according tothe flame characteristics desired. It has been found that i rotation of the tertiary fluid assists in maintaining a short flame and that the ame shape may be *adjusted by varying the amount and direction of rotation of the tertiary fluid.

4The use of air ory the tertiary fluid also facilitates ignition by creating a richer mixture through the burner tube and thus permits the burner to be operated at la lower capacity. Hence,

through Vanes 6I and the annular passage il at a wider range between maximum and minimum capacity is obtained than would be the case if all of the air from chamber I2 were supplied through the air register as secondary air. The proportion of tertiary to secondary air is variable to conform to the ignition characteristics of the fuel insuch a way as to avoid either loss of .ignition or baci; burning. The tertiary fluid yalso shields-the tile surface of the burner throat from the pulverized fuel land prevents the accumulation -oflash on the refractory throat. i l

Usually it is possible to set the tertiary air dampers andregister doors I 6 at predetermined positions and to vary the ow of secondary and tertiary air throughout the capacity range of ,the burner solelyby varying the air pressure inthe wind box or plenum chamber.

Air for combustion is supplied through the air register l5. The primary or `tertiaryfluid may, however, be inert or other ,than air depending upon the required conditions.

What is claimed is: i

l.. A fuel burner comprising a burner tube adapted to connect with a combustion chamber, means forming an annular fuel channel-at the entrance end of said burner tube open throughout its entire inner periphery for the unrestricted flow of fuel radially into said burner tube and formed by a pair of similar spaced annular transverse Wallsrone of which extends yentirely around and radially. outward from the endof saidburner tube to form a continuous fiat annular .baffle .of substantial radial extent around its entire periphery over which the fuel flows before entering .said tube, said baifle having its inner edge substantially iiush with said tube at the entrance end thereof, the other of said Walls being spaced-beyond the end of said burner tube, and a peripheral wall of progressively decreasing radius joining said transverse walls to form an outer closure i for said chamber, said peripheral wall lyingsubstantially beyond the periphery of said tube around the ena v tire periphery thereof so as toprovide a continuious annular fuel channel `for the recirculation of fuel lying entirely beyond` the Iperipheryof the burner tube, a fuel inlet duct carrying` a stream of fuel suspended in a carrying lfiuid coirimuni-- cating tangentially rwith said annular chamber at its point of greatest radial width to cause.- the fuel to rotate in said chamber and to pass radially inwardly therefrom into said burner tube, and air admission means located substantially er1--A tirely in advance of said fuel chamber. to leave said chamber unobstructed and having `I neansv supplying a rotating air stream axially to said annular passage for mixing withythe fuel las `it flows therefrom into said burner tube.

2, A fuel burnerV Comprisinfa-burner tube adapted to connect with a combustion chamber,

burner tube and having means to supply a rotatair admission means located in advance of said ing air stream axially to said burner tube, means forming an annular fuel channel between said burner tube and said air admission means open throughout its entire inner periphery to said ro tating air stream, a fuel inlet duct carrying a stream of fuel suspended in a carrying fluid communicating tangentially with said annular channel, said annular channel decreasing progressively in radial extent from said inlet duct around its circumference, but having a substantial minimum radial extent so as to provide a continuous annular channel for the re-circulation of fuel around said channel entirely beyond said rotating air stream, said channel being adapted for the uniform admission of fuel around its periphery radially inwardly into said burner tube.

ROBERT C. VROOM. JOHN DUNN.

REFERENCES CITED UNITED STATES PATENTS Number Name Date 1,680,964 Wickland Aug. 14, 1928 1,779,647 VanBrunt Oct. 28, 1930 1,795,454 VanBrunt Mar. 10, 1931 1,843,662 Craig et al Feb. 2, 1932 1,870,013 Keenan, Jr. Aug. 2, 1932 1,910,893 Frisch May 23, 1933 1,971,328 Byrne et al. Aug. 28, 1934 2,041,535 Frisch May 19, 1936 2,320,575 Dunn June l, 1943 

